Even with a very small online stake, you still have a chance to be selected to propose a block on Algorand.
Thanks to Pure Proof-of-Stake and VRF-based cryptographic sortition, every participating account has a chance to be selected, with the probability proportional to its online stake.
The 30,000 ALGO minimum applies to earning direct staking rewards, not to participating in consensus.
That's the beauty of PPoS.